# Add a code block here, if required
>>>import threading
>>>x=threading.Barrier(parties=0.5)
Traceback (most recent call last):
  File "<pyshell#0>", line 1, in <module>
    x=Barrier(parties=0.5)
ValueError: parties must be > 0

class Barrier:
    """Implements a Barrier.

    Useful for synchronizing a fixed number of threads at known synchronization
    points.  Threads block on 'wait()' and are simultaneously awoken once they
    have all made that call.

    """

    def __init__(self, parties, action=None, timeout=None):
        """Create a barrier, initialised to 'parties' threads.

        'action' is a callable which, when supplied, will be called by one of
        the threads after they have all entered the barrier and just prior to
        releasing them all. If a 'timeout' is provided, it is used as the
        default for all subsequent 'wait()' calls.
        #if not isinstance(parties, int):
        #        raise TypeError("parties must be an integer")
        if parties < 1:
                raise ValueError("parties must be > 0")

        """
        self._cond = Condition(Lock())
        self._action = action
        self._timeout = timeout
        self._parties = parties
        self._state = 0  # 0 filling, 1 draining, -1 resetting, -2 broken
        self._count = 0